Collapsible containers



July 16, 1963 J. A. MITCHELL 3,097,577

COLLAPSIBLE CONTAINERS Original Filed Dec. 14, 1954 5 Sheets-Sheet l rz; fl

o I {p 4 INVENTOR. JAMES A. MITCHELL V a ggwmy ATTORNEY July 16, 1963Original Filed Dec. 14, 1954 J. A. MITCHELL COLLAPSIBLE CONTAINERS 5Sheets-Sheet 2 Ill y; INVENTOR. JAMESAMITCHELL ATTORNEY July 16, 1963 J.A. MITCHELL v 3,097,577

COLLAPSIBLE CONTAINERS Original Filed Dec. 14, 1954 s Sheets-Sheet 3INVENTOR. JAMES A. MITCH ELL WWW/A A T TORNE V July 16, 1963 J. A.MITCHELL 3,097,677

COLLAPSIBLE CONTAINERS Original Filed Dec. 14, 1954 5 Sheets-Sheet 4INVENTOR.

JAMES A. MITCHELL mwm A 7' TORNEY July 16, 1963 J. A. MITCHELL 3,

' COLLAPSIBLE CONTAINERS Original Filed Dec. 14, 1954 5 sheets-shei 5lNVENT JAMES A.MIT LL J4 TTORNEY 3,097,677 COLLAPSTBLE CONTAINERS JamesA. Mitchell, Englewood, N.J., assignor to Union Carbide Corporation, acorporation of New York Application Jan. 17, 1957, Ser. No. 634,707, nowPatent No. 2,957,282, dated Oct. 25, 1960, which is a division ofapplication Ser. No. 475,183, Dec. 14, 1954, now Patent No. 2,875,562,dated Mar. 3, 1959. Divided and this application Aug. 11, 1960, Ser. No.48,922

4- Claims. (Cl. 150-4) This invention relates to apparatus for handlingand shipping materials likely to be contaminated by fly ash and dustparticles in the air or materials which are likely to be objectionableor a hazard; the present application being a division of my applicationSerial No. 634,707, filed Jan. 17, .1957, now Patent No. 2,957,282,which in turn is a division of my application Serial No. 475,183, filedDecember 14, 1954, now Patent No. 2,875,562.

One object is to provide apparatus for reducing such danger ofcontamination. A further object is to reduce any explosive or otherhazard. Another object is to simplify and reduce the expense of handlingand shipping such material especially in granular form. A further objectis to provide apparatus for transporting material to lessen lossespecially in handling such resins as polyethylene andpolyvinylchloride.

For about a decade the handling and shipping of a resin such aspolyethylene has presented a difficult problem. One reason is the dangerof it being contaminated by ily ash and dust particles in the air. Someregard that danger as being more acute than is the danger ofcontamination with food products. Small particles of foreign matter in athin translucent polyethylene coating are objectionable and becomeconspicuous. Other resins having the danger of being contaminated but toa lesser extent include polyvinylchloride, polystyrene, phenolic moldingpowders, and other materials. The immediately prior method of shipmentfor polyethylene has been in kraft paper bags coated on the inside witha layer of polyethylene to reduce the danger of bits of fiber coming ofiof the paper and getting into the material. When such bags are open orwhile being tied, there is danger of the material being contaminatedfrom the air and from fibers off of the string used for tying the bag.Some breakage of the paper bags and loss of much of the resin thereinhas seemed to be inevitable. Other types of containers have beenconsidered unsuitable. Ferrous metal containers are open to some of thesame objections and are also in danger of contaminating this resin fromparticles of rust that may flake oil. Non-rusting alloy containers havebeen considered but these are usually too expensive and not alwaysadapted to be gas tight. Fibrous containers made of cardboard,paperboard, wall board or the like are not mechanically strong ifreasonably priced and are open to some of the same objections mentionedabove for the paper bags.

Another container given consideration has been the laminated collapsiblerubber container made according to the patents of Cunningham 2,612,924and 2,613,169, both dated October 7, 1952. These were found to beunsuitable in the initial stage of development for a number of reasons.First, the container had no sleeve valves for permitting it to be usedin a completely enclosed solid materials handling system. Secondly, thecontainer size as proposed by Cunningham was too large to permitshipment by truck methods. Thirdly, while the container did contain agas check valve similar to tire valve construction, it was toundunsuitable in that it did not permit inflation of the container in anybut its completely closed stage. Fourthly, the initial containerproposed was manufactured of neoprene lining with tire rubber carcass.This construction was not felt suitable due to migration of 3,097,677Patented July 16, 1963 ice contaminates through the neoprene liner. Inconclusion, therefore, the Cunningham type container, as manufactured bythe US. Rubber Company, contained no provisions to permit use in closedsystem handling and was of such construction that it did not fullyeliminate potential contaminates.

When such rubber bag type container is being filled with materialthrough a top filling opening, any nitrogen or other inert gas used toinflate the container becomes mixed with air unless the inert gas fillsthe room in which the filling operation takes place or unless such gasis fed into the container with the material from its storage bins andconveyors. The idea of the filling room containing nitrogen wasdismissed because a human operator is needed to take care of normaloperation and of emergencies that may develop. The second expedient ofhaving inert .gas supplied with the material through the same supplyline was believed unsuitable because of the danger of leaks developingin a Wide area of hermetically sealed storage bins, conveyors, valves,and the like. Such a leak is objectionable both from the safetystandpoint as well as an economic one because the greater the danger ofleakage, the greater is the danger that air may get into the sealed areaand increase the explosive hazard. Polyethylene when freshly made givesoff ethylene gas constituting an explosive hazard when mixed with anoxidizing gas. Having an inert gas supplied with the filling materialrequired two sources of inert gas in event a higher pressure is desiredin the container after it has been filled than is provided duringfilling, and for inflation before filling.

According to this invention the contamination and the explosive hazardshave been minimized and resin loss has been greatly reduced. Moving agas check valve to a location independent of the closure for the fillingopening enables an excess of inert gas to be supplied to the containerbefore, or during, and after the filling takes place. Enlarging the sizeof this valve'has shortened the time for inflation. A gas impervioussleeve secured to a metal ring around each of the filling and emptyingopenings, is tied or clamped near such ring to retain gas pressure andmaterial in the container after a gas-tight closure has been removed andbefore a gas-tight connection has been made to a filling or emptyingpipe with the aid of an outer end portion of such sleeve. A rotatingvane is placed within the container during filling to distribute orthrow the resin particles against the side walls. When the materialbeing supplied to the container reaches a level as high as that of therotating vane or paddle, it impedes movement of the vane, causing anoverload circuit breaker to stop the supply of material and vanerotation. This vane can then be withdrawn with the aid of said sleevefrom the container without loss of much of the gas pressure.

Referring to the drawings:

FIG. 1 is a diagrammatical representation of apparatus for washing andfilling collapsible containers under this invention;

FIG. 2 is a side view of a collapsible container mounted in a tiltingcradle during the'filling operation;

FIG. 3 is a section through a preferred dorm of collapsible containeremployed in the process and apparatus of this invention;

FIG. 4 is a section on the line 44 of FIG. 3;

FIG. 5 is a section on the line 5-5 of FIG. 3;

FIG. 6 shows the sling used for holding the container while beingemptied;

FIG. 7 shows the container in nearly collapsed condition;

FIG. 8 shows the container in substantially completely collapsedcondition;

FIG. 9 is a detail of the cable connections at the top and bottom of thesling device of FIG. 6;

FIG. 10 illustrates the resin disperser for distributing material beingsupplied through the filling pipe into the container;

FIG. 11 is a detail showing the expansible lower end of the filling pipecapable of holding the upper end of a flexible sleeve or otherconnection between the container and the filling pipe;

FIG. 12 is a longitudinal section through the washing fixture 13 shownin FIG. 1;

FIG. 13 is a side view of a vibrating support used in another Way ofemptying the container; and

FIG. 14 is a top plan view of the device of FIG. 13.

A collapsible container 10 is of the general type illustrated in thepatent to Cunningham 2,612,924, dated October 7, 1952, except forcertain hereinafter mentioned details. This container preferablycontains no natural rubber but is formed from layers of fabric betweenlayers of chemical rubber or layers of other flexible plastics andespecially that known commercially as neoprene. When filled thiscontainer will hold about 296 cu. ft. of granular polyethylene. Its sidewalls are about one-quarter of an inch thick and the container willexpand to a diameter of about 89 inches or for about 3% to 5% increasein volume. When filled it will hold about 11,000 pounds of polyethylene.At the top of the container is an appropriate hook or supporting eye 11by means of which the filled container may be suspended from above by acrane or lifting truck in handling it. At the lower central part of thecontainer is a discharge opening 12. As shown in FIG. 1 a washingfixture 13 is located adjacent and to one side of a pair of tiltingcradles 14. By means of hydraulic or pneumatic mechanism 15 the cradleand container may be swung about the cradle trunnions illustrated inFIG. 1 to bring the filling opening 16 uppermost as shown in FIG. 2. Aflexible connection 17 permits the supply of inert gas for inflating andfor supplying such gas during or after filling the container. A supplypassageway or filling pipe 18 is provided at its lower end portion 19With a generally rigid fitting for connection with the filling openingas hereinafter described. Granular polyethylene of the size of about ofan inch cube with rounded corners is supplied from storage bins or otherequipment by the screw conveyor 20 shown in FIG. 2. A rotatable feedervalve sometimes called an air lock or rotatable gate valve 21 enablessmall batches of the material to be fed into the supply line andcontainer without allowing substantial escape of gas pressure fromwithin the container 10. A magnetic separator 22 is provided to extractany ferrous particles that may have flaked off from any storage bin orprevious handling equipment. Adjacent to but displaced slightly from thefilling opening 16 is a gas check valve 23 somewhat similar in functionto an ordinary tire valve but made larger in diameter or about an inchand a half in diameter to enable the inflation operation to be performedmore quickly than would be possible with any tire valve known. With sucha gas check valve it is possible to inflate and expand this containerfrom its collapsed condition in about a minute using preferably an inertgas such as nitrogen under a low pressure of about one or two pounds persquare inch. Within the container 10 are supporting cables 24 extendingbetween the fitting 11 and bottom portions of the container thusenabling the load to be distributed over the bottom area. Surroundingeach place of attachment of a supporting cable 24 is a metalreinforcement 25.

As shown in FIG. 4 the filling opening 16 has a metal ring 26surrounding it and clamping edge portions of the opening in container 10between the n'ng 26 and a cooperative inner ring 27 extends upwardly toprovide a seat for the outward flange of the closure or cap 29 with agasket 30 between this flange and ring 27. An expansible spring ring 31holds the inner end portion of a flexible substantially gas-imperviousnylon sleeve 32 in place. In-

termediate the outer or upper end of the sleeve 32 and lower end of thesleeve 32 are draw string ends 33. Normally, the sleeve 32 is carried inthe container 10 with the draw string 33 closing the sleeve against theescape of gas. It is the fact that the draw string 33 is located closeto the container that enables the draw string when closed and theclosure 29 is in place to support the rest of the sleeve 32 as shown indotted lines in the lower part of FIG. 4. Instead of a draw string 33 aclamp or other removable means for closing the sleeve 32 may be used toprevent substantial escape of gas from the container while the sealingcover 29 is not in place over the filling opening. The sleeve 32 ispreferably provided with a thin soft plastic surface to enable thegathering Or clamping of the sleeve to be substantially gas-tight. Whenclosure 29 is removed the sleeve 32 maybe extended outwardly through thefilling opening.

The portion of the sleeve 32 above the draw string 33 in FIG. 4 isplaced around the lower end of the supply line 18 and a draw string 34may be located adjacent the top of the sleeve, and may be tightened andtied, thereby constituting compression means, to keep gas within thecontainer from escaping. After the upper or outer end of the sleeve isgas-tightly secured, the lower draw string is then untied. Instead of adraw string at the outer end, sleeve 32 preferably makes a gas-tightjoint with the fitting 19 by means of an outwardly expansible band asshown in FIGS. 10 and 11 and hereinafter described. Neither the sleeve32 nor its draw string needs to be absolutely gas-tight as a small leakis not objectionable.

The gas check valve is shown in FIG. 5 as being provided with a clampingring 35 and a second clamping ring 36 between which the adjacent edge ofthe material of the container 10 is securely held in place. Anappropriate packing strip 37 prevents gas leakage from the containeroutwardly around the threaded portion of the ring 35. Radial vanes 33support a guide bearing 38:: for the stem 39 and the spring 40 biasesthe movable valve element 41 with a yieldable seat material 42 to aclosed position. The gas supply line 17 is provided with a metal fitting43 on its end portion having a flange containing a packing ring 44 sothat on attachment to the container gas check valve a gas-tightconnection is made. At its outer end this gas check valve has asegmental outwardly directed flange 46 beneath which the segmentalclamping ring 45 is held. The ring 45 and flange 46 are shaped in acustomary manner so that upon angular displacement of one with respectto the other it is possible to separate quickly the clamping ring fromthe gas check valve. Projecting handle portions 47 provide a convenientgrip by means of which the clamping ring 45 may be rotated in attachingthe same to the gas check valve 23 and its flange 46.

A discharge sling includes a supporting ring 48 around the dischargeopening 12 in the bottom of the container 10 from which divergeprojections 49 of the shape illustrated in FIG. 9 for the attachment ofcable connection 50 thereto so that cables 51 may extend around theoutside of the container at angularly spaced positions as shown in FIG.6 during a discharge operation. Pins 52 hold the terminal connections 56to the projections 49. Also shown in FIG. 9 is an upper fitting 53welded or otherwise secured to the supporting eye 11a or hook having thesame number of projections 54 as does the lower ring. Here again upperterminal connections 55 are held to the projections 54 by pins notnumbered. With the bottom ring 48 in position on a suitable support andthe lower cable portions 51 diverging therefrom, a filled container isplaced in substantially axial alignment with the ring 48. The upperfitting 53 and the upper cable portions are then placed over the top ofthe container. Pins 56 then connect each upper cable portion with itscorresponding lower cable portion. When the cable portions are allconnected the entire apparatus constitutes a sling by means of which thefilled container may be raised while suspended from above. The dischargeopening 12 is similar to the filling opening in being provided with agas sealing closure, and a sleeve to retain gas pressure before aconnection is made to a discharge line. Upon removing the cover from thedischarge opening 12 in the lower portion of the container, the spacedsupporting cables eifect la squeezing action upon the filled containertending to form flutes or grooves in the sides of the containerfacilitating the discharge of material from the suspended container. Thepartially collapsed container is shown in FIG. 7 while FIG. 8 shows thecontainer in substantially completely collapsed position in which itoccupies only about 12% of the space it occupies when inflated.

In FIG. 10 is shown a resin dispenser comprising rotatable vanes 57mounted within the container 110- 'on the lower end of a rotatable shaft58 driven by the flexible drive shaft 59 from a motor 60. The supportingcolumn 61 on which the motor is mounted is adjacent two or morecontainer filling positions. Cantilever supporting arm 62 has its outerportion 63 pivoted at 64 in order that the arm 63 may be swung from onefilling position to another. The arm portions 62 and 63 are not usuallyin alignment whereby the supply line 65 may be adjusted in a directionnormal to the plane of the paper as well as radially toward or from thecohunn 61. The shaft 58 is shiftable in order that the rotatable vanes57 may be raised from a position within the container to a positionoutside of it as shown in dotted lines in FIG. 10. The bearing for theshaft 58 where it passes through a supply line 65 permits the shaft 58to be slidable therethrough when not rotating. A pin through shaft 58suffices to hold the vanes 57 in their upper position. Supply line 65leads from any source of material such as a storage bin or conveyor intoa location above a container to be filled so that a sleeve 32 may beattached to the lower end of the supply line 65 with a substantiallygas-tight connection. In FIGS. 10 and 11 instead of tying the upper endof the sleeve 32 to the lower end of the supply line 65, the lower endof the supply line is provided on its outer surface with an expansibleband 66 to make a gas-tight connection with the sleeve 32. Gas underpressure is supplied through the pipe 67 to the inner surface of theexpansible band 66 and as pressure is applied the band '66 bulgesradially outward into a tight contact with the inner surface of thesleeve 32. The gas line 67 is provided with a valve having a controlhandle 68 and is supplied through a pressure line 69 from any convenientsource of gas under pressure.

The washing fixture 13 shown in FIG. 12 comprises a fog type spraynozzle 76 supplied by the pipe 71 from a surge tank 80 or other sourceof liquid pressure. The purpose of the tank 80 is to provide an adequatesupply of washing water under about 50 or 60 pounds per square inch insuflicient quantity for the entire operation. Around the nozzle 70 is adrain pipe 72. It is expected that the use of this washing fixture willbe required only when the container content is changed from one type ofmaterial to another. For instance, care is used to see that polyethyleneof one kind is not mixed with the samematerial of another kind ormolecular weight. In use it is expected that an inflated empty container10 will be suspended over the washing fixture 13 and upon removal of thecover from the discharge opening of the container 10, the clamping ringaround the discharge opening or a sleeve will fit over the upper end ofthe drain pipe 72. It will be understood as stated previously, that thedischarge opening is of substantially the same size and construction asis that shown for the filling opening. After the outer ring around thedischarge opening or a sleeve has been placed over the drain pipe 72,gas under pressure is admitted through the pipe 74 to extend theflexible band 73 outwardly into substantially water and gas-tightcontact with the clamping ring or sleeve from around the dischargeopening. The outer tube is provided with a sight glass for determiningthe condition of the discharge drain water; this outer wall around theinner pipe 76 is of glass as shown at 75. Drain Water follows thedirection of the arrows in FIG. 12 and moves upwardly within the glasswall 75 and outside the pipe 76 to the water discharge pipe 77. Thebottom of the washing fixture is provided with a drainage pipe 78connected to the base 7 6a thereof. A turbulent flow is planned in theinner tube 76 and a laminar flow in the outer passage between the glass75 and the inner pipe 76 in order that the condition of the liquid andany suspended matter may be visible. After washing the inside of aninflated container, water is turned oif and heated air supplied throughthe pipe 71 from a heater unit or exchanger 79 (FIG. 1) to dry out theinside of the container by a blast of air heated to some convenientamount such as about 200 F. A hose 81 supplies air for inflation beforeand during washing, and after Washing heated air is supplied to pipe 71.After drying the container, the air is urged in any of several Waysfamiliar to those skilled in this art before nitrogen is supplied.

In FIGS. 13 and 14 the ring 82. is adapted to extend around the clampingring of the discharge opening in the bottom of the container. From thisring radial upwardly inclined bars 84 constitute supports for a filledcontainer and these bars are capable of functioning for somewhat thesame purpose as the cables in the sling suspension of FIGS. 6, 7 and 9.This vibrating support does not need to begin its movement until aroundof the container contents has been discharged. The upper portion of thecontainer collapses as material is discharged when it settles down intothe support. These bars engage the container above and outside thedischarge opening and are capable of applying a squeezing action to thelower portion of the container Walls. A motor 83 drives mechanism forvibrating the supporting bars 84 and container 10 with an amplitude ofabout 1 inch at a frequency of between and 300 vibrations per minute.The container and supporting bars 84 during vibration are moved alongthe guide rails 85 and 86 shown at the top and bottom in FIG. 14.

A collapsed container as shown in FIG. 8 is preferably suspended fromabove and inflated with an inert gas such as nitrogen by attachment ofthe gas supply line 17 to the check valve fitting 23 shown in FIG. 5.This check valve is about an inch and a half inside diameter so that theinflating of the container may be accomplished in a relatively shortinterval. Upon inflation the pressure in the inflated container is quitelow being onlybetween about one and two pounds per square inch. It willbe understood that if the collapsed container is in need of washing itwill be placed over the washing fixture 13 in the manner described abovebefore or after being inflated. Due to some of the inflating gas beingabsorbed and carried off by the wash water some gas may need to besupplied during washing. After being inflated and washed, if necessary,the cover 29 of the filling opening 16 is removed and the collapsedsleeve pulled outwardly from the filling opening. At this time no largequantity of gas leaks out because the draw string 33 is tied tightclosing the gasimpervious sleeve against substantial leakage. The upperend of the sleeve is then placed around the fitting 19 at the lower endof the material filling line and held in substantially gas-tightconnection with the outside of such filling line by either tying theupper draw string 34 or by having the upper end of the sleeve held ingas-tight connection with the outside of the filling line by anexpansible band 66 as shown in FIG. 11. After the upper end of thesleeve has been made to have a gas-tight connection with the fillingline, lower draw string 33 is untied to release gas pressure within thecontainer. Pressure in the filling line is prevented from going far byreason of the rotary feeder valve 21 to maintain the filling line 18 or65 between this rotary feeder valve and the container under slightlysuperatmospheric pressure. During the filling operation inert gas issupplied gradually and continually or intermittently from time to timeas needed to prevent air leaking into the container and lower fillingline. The rotary feeder valve 21 is driven at a speed of about 6 rpm. inorder to fill the container with approximately 11,000 pounds of granularpolyethylene in about twenty minutes.

Stoppage of the supply of material to the container is effected in oneor more of several ways. For example the material may be packed in thesupply line 18 up to the rotary feeder valve 21 and cause this rotaryvalve to stop by jamming and in response to an overload circuit breakergoing out and stopping the motor driving the feeder valve. Due to thecontainer being slightly expansible, the container may be vibratedslightly by a kick or otherwise and the small fraction of about 1% ofmaterial in the lower end of the supply line will fall into thecontainer. While the inside of the supply line is approximately 6 inchesin diameter its cubical contents is less than 1% of the volume of thecontainer and the container is adapted to be expanded about 4% bothlinearly and volumetrically. The result is that after a kick or othervibration of the filled container the material in the supply line belowthe rotary feeder valve is allowed to fall into the container on itsbeing slightly vibrated and expanded. Another way in which the supply ofmaterial to the container is shut off automatically is in response tothe level of [granular material reaching the height of the resindisperser 57 shown in FIG. 10. There are preferably two vanes rotatingat 1800 rpm. At that time the material jams and stops rotation of thedistributor 57 and shaft 58 by a circuit breaker stopping the motor 66.The purpose of the rotating vanes 57 is to prevent the granular materialpiling up at the mouth of the container. Instead it causes incominggranules to be thrown outwardly to the periphery of the container. Afterthe material rises to stop the disperser 57, the shaft 58 is raised tohold the vanes 57 in the dotted line position in FIG. 10. The drawstring 33 is then tied to close the sleeve between the top of thecontainer and the elevated vanes. After tying the draw string 33 the airpressure under the band 66 is released allowing the sleeve 32 to fallinto the container when it will occupy the dotted line in position shownin FIG. 4.

After filling, a crane or lifting truck will remove the filled containerfrom the tilting cradle of FIGS. 1 and 2 to either a storage yard or toa ship, barge, rail car or motor truck. With containers of the sizementioned it is possible to :get seven of them in alignment in an openrail car of the type having short sides and commonly known as a gondolacar. Most industrial users of polyethylene will have or can justifyobtaining a suitable lifting truck or a crane whereby the container canbe handled in the described manner.

For emptying, the container is placed in the sling of FIG. 6 asdescribed above. Upon removal of the cover from the discharge opening inthe bottom of the container the same type sleeve shown and described inconnection with the filling container is drawn out and gas-tightlysecured to a discharge line. During emptying of the container the inertgas is not ordinarily supplied to the container because the residualamount there is discharged with the material, although gas may besupplied if desired. Instead of using the sling of FIG. 6 during theemptying of a container the vibrating support shown in FIGS. 13 and 14may hold the container and its contents, when the ring 82 extends aroundthe discharge opening in the bottom of the container. The latteremptying apparatus is quicker than the sling of FIG. 6 which takes moretime to place the container in the sling and remove it therefrom. TheFIG. 6 construction is preferable where the container can displace theneed for a storage bin and the rate of discharge is controlled by therate of consumption.

It has been found desirable that the container be free of natural rubberand have all its plies comprised of chemical rubber known as neoprene.The tilting cradle shown in FIGS. 1 and 2 may be vibrated as is thecontainer support of FIGS. 13 and 14 in order that during filling thematerial may be packed as tightly as is conveniently possible. The 86inch diameter container will expand to a diameter of about 89 incheswhen filled with granular polyethylene and would expand to as large as90 inches in diameter when filled with water. Other materials thanpolyethylene and the resins mentioned are adapted for shipment under theabove described process of filling, transporting and emptying materialsout of contact with the atmosphere.

Among the advantages of this invention may be mentioned the much desiredgreater freedom from contamination by the totally enclosed filling,transporting and emptying apparatus and system for solid materials. Theexplosive hazard is minimized. After the container has been collapsedthe cover for the discharge opening is usually replaced and the residualinert gas or nitrogen is retained. Any air that may have leaked into thecollapsed container will be in such small quantity that any dilutedethylene gas and oxygen present no explosive hazard on again inflatingthe container with nitrogen and filling it. A greatly reduced resin lossof nearly 1200% is possible. Reduction in such loss is an importantfactor in the present invention. With the large size containersmentioned above one such container is capable of replacing about 200 ofthe paper bags formerly used in the transportation of polyethylene. 40%to 50% of the shipping costs with paper bags is estimated to be saved.No elaborate handling equipment is needed by a user of the describedfilled container because nearly every such user has a lifting truck orcrane by means of which the filled containers may be lifted out of arail car and moved to the place Where they are to be used. In shippingcalcium chloride for example instead of nitrogen the container will befilled with dry air. The expansibility of the container is useful inenabling the material to be well packed herein. The use of two openingsone for filling and one for discharge permits the filling and emptyingof the container without the necessity of having more elaborateequipment to invert it. Preferably a fiuid pressure regulator limits thegas pressure in the container to a maximum of seven or eight pounds persquare inch. After being filled the pressure of inert gas in thecontainer is usually raised to about five pounds per square inch. Anyoverload circuit breaker not only stops rotary feed valve 21 but alsoany and all conveyors 20 supplying material.

What is claimed is:

1. A gas-tight shipping container of the collapsible type capable ofretaining therein a gas under superatmospheric pressure while it isbeing filled with solid material, said container having a fillingopening surrounded by a metal ring, a gas check valve outside said ring,a substantially gas-tight closure removably secured to said ring andaccessible from outside said container, a flexible sleeve ofsubstantially gas-impervious material having one end portionsubstantially gas-tightly secured to said ring within said closure,means for substantially gas-tightly closing said sleeve adjacent saidring to provide a pouch for supporting the outer portion of the sleevewithin the container, when the sleeve is closed and such outer portiontucked therein, the outer end portion of said sleeve being adapted to besubstantially gas-tightly fitted around the outside of a filling oremptying pipe, whereby after the sleeve outer end portion has beenfitted to said pipe said sleeve closing means may be opened for themovement of material through said sleeve.

2. A container comprising a full closed relatively thick walled plasticenvelope having an opening containing a ring the edge of which isprovided with a relatively thin walled tubular substantially longflexible sleeve, draw string means for closing such sleeve between theends thereof against the flow of gas to seal said opening, leaving thetubular outer end portion of said sleeve free, and compression meansincluding a soft plastic surface on the inner side of such sleeve forconnecting said free 10 end portion in essentially gas-tight relationwith a pipe 2, including a cap for covering the inside of said ring forconducting material through said sleeve when said when the flexiblesleeve is closed by said draw string draw string closure means isreleased, whereby c0ntamimeans and tucked wtihin the ring and under saidcap. nation of such material from the outside 1s mhibited by ReferencesCited in the file of this patent complete isolation thereof duringtransfer of the material 5 through said sleeve, as well as duringstorage of such UNITED STATES PATENTS material within such container.1,965,040 Kelly July 3, 1934 3. A container as defined by claim 2, inwhich said 2,209,570 Kraft July 30, 1940 envelope is collapsible andprovided with a gas check 2,435,490 Beager et a1. Feb, 3, 1948 valve inthe wall thereof spaced from said sleeve. 10 2,574,931 Nason Nov. 13,1951 4. A gas-tighht shipping container as defined by claim 2,724,418Krupp Nov. 22, 1955

1. A GAS-TIGHT SHAPING CONTAINER OF THE COLLAPSIBLE TYPE CAPABLE OFRETAINING THEREIN A GAS UNDER SUPERATMOSPHERIC PRESSURE WHILE IT ISBEING FILLED WITH SOLID MATERIAL, SAID CONTINER HAVING A FILLING OPENINGSURROUNDING BY A METAL RING, A GAS CHECK VALVE OUTSIDE SAID RING,SUBSTANTIALLY GAS-TIGHT CLOSURE REMOVABLY SECURED TO SAID RING ANDACCESSIBLE FROM OUTSIDE SAID CONTAINER, A FLEXIBLE SLEEVE OFSUBSTANTIALLY GAS-IMPERVIOUS MATERIAL HAVING ONE END PORTIONSUBSTANTIALLY GAS-TIGHTLY SECURED TO SAID RING WITHIN SAID CLOSURE,MEANS FOR SUBSTANTIALLY GAS-TIGHTLY CLOSING SAID SLEEVE ADJACENT SAIDRING TO PROVIDE A POUCH FOR SUPPORTING THE OUTER PORTION OF THE SLEEVEWITHIN THE CONTAINER, WHEN THE SLEEVE IS CLOSED AND SUCH OUTER PORTIONTUCKED THEREIN, THE OUTER END PORTION OF SAID SLEEVE BEING ADAPTED TO BESUBSTANTIALLY GAS-TIGHTLY FITTED AROUND THE OUTSIDE OF A FILLING OREMPTYING PIPE, WHEREBY AFTER THE SLEEVE CLOSING MEANS BY OPENED FOR THEMOVEMENT OF MATERIAL THROUGH SAID SLEEVE.